This invention relates to rotary mechanisms, and, more particularly, to improved clamping means for clamping the end housings of such mechanisms to the center housing, particularly in so-called "crowded" areas such as where ports, ignition devices, fuel injection devices, or the like are located. Prior art of relevance includes the following U.S. Pat. Nos. 3,513,814 to Jones, issued May 26, 1970; and 3,400,692 to Jones, issued Sept. 10, 1968.
A typical rotary mechanism, such as a rotary engine, compressor, or pump, or the like, has an operating chamber defined by a center housing flanked by a pair of end housings. In a typical construction, the end housings are clamped to the center housing by means of bolts extending through both end housings as well as the center housing.
Bolt spacing must be reasonably close to avoid gas leakage and to prevent structural failures of the housings themselves. In addition, where a coolant is used, the bolt spacing must be sufficiently close as to prevent coolant leakage.
In a typical engine, there are instances where bolt spacing must be greater than desired for the reason that there is not sufficient room for both through bolts and other necessary structural features such as ports as, for example, the intake and exhaust ports in a rotary engine, a swirl chamber, a fuel injector or a spark ignition device, or the like.
In some instances, this problem has been overcome through the use of short bolts extending only through one end housing and partially into the center housing. This solution is not altogether desirable in that suitable bosses must be provided in the center housing and accordingly take up valuable space therein.
Other solutions have been proposed as well. For example, in one of the previously identified patents, it is proposed that there be employed an elongated clamp extending between two bolts with one or more button-like structures interposed between approximately the midpoint of the clamp and the end housing so that an appropriate clamping force is applied to the end housing intermediate the bolt locations. While this solution represents an improvement, it is subject to two problems. Due to high localized forces and contact stresses, as well as some unavoidable relative motion between the parts during operation of the mechanism, there is a tendency for fretting or "Brinelling" at the button-like structures. Secondly, large localized forces applied at the button-like structures can overstress the supporting structure of the housing since the forces are not carried by bosses but by structure as ports or the like.
Another proposed solution set forth in the other of the previously identified patent is generally unacceptable because of its bulk.